Method for Detecting Fraudulent Frame Sent Over an In-Vehicle Network System

1. A fraud detection method for use in an in-vehicle network system using Controller Area Network (CAN) protocol, the fraud detection method comprising: receiving at least one data frame sent to a bus; verifying a specific identifier in the received data frame only when the received data frame does not follow a predetermined rule regarding a transmission period and a state of a vehicle having the in-vehicle network system mounted therein is a predetermined state; detecting the received data frame as an authenticated data frame when the verifying is successful; and detecting the received data frame as a fraudulent data frame when the verifying fails, wherein the predetermined state of the vehicle is the vehicle traveling.

2. The fraud detection method according to claim 1 , wherein the specific identifier is disposed in a data field of the received data frame at a predetermined position, and wherein in the verifying, it is verified whether the specific identifier is a message authentication code that reflects information in the received data frame.

3. The fraud detection method according to claim 1 , wherein the specific identifier is disposed in a data field of the received data frame at a predetermined position, and wherein in the verifying, it is verified whether the specific identifier is same as a predetermined value.

4. The fraud detection method according to claim 1 , wherein the specific identifier is disposed in a data field of the received data frame at a predetermined position, and wherein in the verifying, it is verified whether the specific identifier is same as a counter value that reflects a number of times at which data frames that do not follow the predetermined rule are received.

5. The fraud detection method according to claim 1 , wherein the at least one data frame sent to the bus comprises a plurality of data frames, wherein in the receiving, the plurality of data frames is sequentially received, wherein the specific identifier is disposed in a data field of the received plurality of data frames at a predetermined position, and wherein in the verifying, it is verified whether the specific identifier is same as a value obtained through a predetermined calculation based on a specific identifier in a data frame previously received in the receiving of the plurality of data frames.

6. The fraud detection method according to claim 1 , wherein in the verifying, it is determined whether the received data frame follows the predetermined rule, wherein when it is determined that the received data frame does not follow the predetermined rule, it is determined whether the state of the vehicle is the predetermined state, and wherein when it is determined that the state of the vehicle is the predetermined state, the verification is performed on the specific identifier.

7. The fraud detection method according to claim 1 , wherein when the received data frame follows the predetermined rule, the received data frame is detected as being an authorized data frame.

8. The fraud detection method according to claim 1 , wherein in the verifying, when the received data frame does not follow the predetermined rule and the state of the vehicle having the in-vehicle network system mounted therein is not the predetermined state, the received data frame is detected as being an authorized data frame.

9. The fraud detection method according to claim 1 , wherein in the verifying, when the received data frame does not follow the predetermined rule and the state of the vehicle having the in-vehicle network system mounted therein is not the predetermined state, the received data frame is detected as being the fraudulent data frame.

10. A method for use in an in-vehicle network system using Controller Area Network (CAN) protocol, the method comprising: providing a specific identifier in a data frame only when a state of a vehicle having the in-vehicle network system mounted therein is a predetermined state and the data frame, that does not follow a predetermined rule regarding a transmission period, is to be sent; and sending, to a bus, the data frame that includes the provided specific identifier and that does not follow the predetermined rule, wherein the predetermined state of the vehicle is the vehicle traveling.

11. The method according to claim 10 , wherein in the providing, a message authentication code that reflects information in the data frame to be sent is disposed in a data field of the data frame to be sent at a predetermined position as the specific identifier.

12. The method according to claim 10 , wherein in the providing, a predetermined value is disposed in a data field of the data frame to be sent as the specific identifier.

13. The method according to claim 10 , wherein in the providing, a counter value that reflects a number of transmissions of data frames that do not follow the predetermined rule in the sending is disposed in a data field of the data frame to be sent at a predetermined position as the specific identifier.

14. The method according to claim 10 , wherein the data frame sent to the bus comprises a plurality of data frames, and wherein in the providing, a resultant value obtained by performing a predetermined calculation on a basis of a specific identifier provided in a data frame previously sent in the sending is disposed in a data field of each of the plurality of data frames.

15. An in-vehicle network system using Controller Area Network (CAN) protocol, the in-vehicle network system comprising: a first electronic controller including one or more memories and circuitry which, in operation, provides a specific identifier in at least one data frame only when a state of a vehicle having the in-vehicle network system mounted therein is a predetermined state and the data frame, that does not follow a predetermined rule regarding a transmission period, is to be sent, and sends, to a bus, the data frame that includes the provided specific identifier and that does not follow the predetermined rule; and a second electronic controller including one or more memories and circuitry which, in operation, receives the data frame sent to the bus and verifies the specific identifier in the received data frame only when the received data frame does not follow the predetermined rule and the state of the vehicle having the in-vehicle network system mounted therein is the predetermined state, wherein when the verification is successful, the second electronic controller detects the received data frame as being an authorized data frame, wherein when the verification fails, the second electronic controller detects the received data frame as being a fraudulent data frame, and wherein the predetermined state of the vehicle is the vehicle traveling.

16. An electronic controller using Controller Area Network (CAN) protocol, the electronic controller comprising: one or more memories; and circuitry which, in operation: provides a specific identifier in at least one data frame only when a state of a vehicle having an in-vehicle network system mounted therein is a predetermined state and the data frame, that does not follow a predetermined rule regarding a transmission period, is to be sent; and sends, to a bus, the data frame that includes the provided specific identifier and that does not follow the predetermined rule, wherein the predetermined state of the vehicle is the vehicle traveling.

17. An electronic controller using Controller Area Network (CAN) protocol, the electronic controller comprising: one or more memories; and circuitry which, in operation: receives at least one data frame sent to a bus; and verifies a specific identifier in the received data frame only when the received data frame does not follow a predetermined rule regarding a transmission period and a state of a vehicle having an in-vehicle network system mounted therein is a predetermined state, wherein when the verification is successful, the electronic controller detects the received data frame as being an authorized data frame, wherein when the verification fails, the electronic controller detects the received data frame as being a fraudulent data frame, and wherein the predetermined state of the vehicle is the vehicle traveling.